Advanced telecommunications networks that are able to deliver higher bandwidths to fixed and/or mobile subscribers require access networks, aggregation networks and core networks that have increased bandwidths. Such increased bandwidth needs can be handled by optical transport networks or optical data transmission networks, especially those using at least two channels, each using a predetermined wavelength, in particular according to a wavelength division multiplex (WDM) scheme or a dense wavelength division multiplex (DWDM) scheme.
In optical data transmission networks, router nodes typically are connected via optical data transmission lines that comprise a series of amplifier nodes arranged one after another. In order to monitor the optical performance of the amplifier nodes, it is necessary to carry out measurements locally at the amplifier nodes. For example, a technician would tap an optical spectrum analyzer onto the monitor port of an amplifier node to check the operational status of the amplifier node in question. However, this approach is rather time consuming, labor intensive and expensive.